Further Investigations on Newton-Raphson Methods in Aircraft Trim

Flight simulation modelling of an aircraft is required for various purposes including performance analysis, flight control design, and flying qualities analysis. The Saab 340B is a twin turboprop transport aircraft designed to seat 30-36 passengers. A Saab 340B has been modified to operate as a flying laboratory for teaching and research purposes at the Cranfield University, United Kingdom. This paper demonstrates a component build-up approach towards creating a simulation model using the data available from the aircraft manufacturer. This approach has previously proven successful in establishing the fundamental working principles of flight dynamics for a Jetstream J31 aircraft. Empirical estimates of the aerodynamic forces and moments acting on the aircraft are calculated from the aircraft's geometrical parameters using Engineering Sciences Data Unit (ESDU) data sheets. The contribution of this study is a systematic approach to developing an aerodynamic model using ESDU and comparing the results with the collected flight test data across the entire flight envelope for the aircraft. Nomenclature 𝑚 = Mass of the air vehicle 𝐼 ̆ = Inertia Tensor 𝑔 ⃗ = Acceleration due to gravity 𝑇 = Thrust force 𝐷, 𝐶, 𝐿 = Aerodynamic drag, crosswind, and lift forces in wind coordinates 𝑋, 𝑌, 𝑍 = Total longitudinal, lateral, and vertical forces in body coordinates 𝑋 𝑎 , 𝑌 𝑎 , 𝑍 𝑎 = Aerodynamic longitudinal, lateral, and vertical forces in body coordinates 𝑋 𝑝 , 𝑌 𝑝 , 𝑍 𝑝 = Propulsive longitudinal, lateral, and vertical forces in body coordinates 𝑋 𝑔 , 𝑌 𝑔 , 𝑍 𝑔 = Aerodynamic longitudinal, lateral, and vertical forces in body coordinates 𝑙, 𝑚, 𝑛 = Roll, pitch and yaw moments in body coordinates 𝑢, 𝑣, 𝑤 = Velocity components along the X-axis, Y-axis and Z-axis in body coordinates 𝑝, 𝑞, 𝑟 = Angular roll, pitch and yaw rates of aircraft resolved in body coordinates 𝛷, 𝜃, 𝜓 = Euler roll, pitch, and yaw angles 𝑉 𝑁 , 𝑉 𝐸 , 𝑉 𝐷 = Velocity components along the X-axis, Y-axis and Z-axis in North-East-Down coordinates 𝑝 𝑁 , 𝑝 𝐸 , 𝑝 𝐷 = X-axis, Y-axis and Z-axis North-East-Down positions ℎ = −𝑝 𝐷 = Altitude

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“…[10], Zipfel [11], Cook [12], Allerton [13], Etkin and Reid [14], Stengel [15], and Millidere, et.al. [16] are some examples.…”

Section: Aircraft Modeling and Trim A Aircraft Vehicle Flight Simulat...mentioning

confidence: 99%

Modelling, Simulation, and Verification of the Saab 340B

Makadia

Millidere

Alam

et al. 2023

AIAA SCITECH 2023 Forum

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“…The purpose of the equation of motion for flight dynamics is to provide sufficient knowledge about the motion of the air vehicle. The purpose of the other subsystem models is to produce air-vehicle data for the equation of motion model [23,24].…”

Section: Flight Simulation Modelmentioning

confidence: 99%

Development of Aerodynamic and Propulsion Models Using the Iterative Equation Error Method

Millidere,

Akgül,

Leblebicioğlu

et al. 2023

Aerospace

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For developing high-fidelity flight simulations, an accurate and complete representation of the aerodynamic characteristics of the aircraft is necessary. To obtain a realistic aerodynamic database, system identification methods can be used to describe the applied forces and moments acting on the aircraft. This study is based on simulated flight test data from a nonlinear simulation of the F-16 aircraft. It is demonstrated that the complete set of aerodynamic coefficients can be reconstructed from the flight test data. Thrust forces and moments are obtained from ground tests. A practical system identification methodology based on the iterative equation error method to determine the nonlinear aerodynamic and engine thrust models in the absence of engine manufacturer data is developed. The estimated values obtained using the method are compared with the actual parameter values. A mathematical engine model that can be used to estimate the thrust force for any flight condition is also developed. The findings demonstrate that the proposed method yields accurate results. The developed methodology is well-suited for the identification of isolated aerodynamic drag and lift coefficients and the thrust model.

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Further Investigations on Newton-Raphson Methods in Aircraft Trim

Cited by 2 publications

References 6 publications

Modelling, Simulation, and Verification of the Saab 340B

Modelling, Simulation, and Verification of the Saab 340B

Development of Aerodynamic and Propulsion Models Using the Iterative Equation Error Method

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